How about hanging "autonomous, unmanned fighters" (heat-seeking missiles) on aerostats for continental defense? Way out at sea for those countries that have coastline? (In the ADIZ)
Remember, the AIM-120 in an improved form has been fantasized as an SRBM interceptor. No combat air patrol necessary, these things can float for months, if not years.
Hey, Lockheed, Think out of the box!